Dementia is not one single illness. It is a general term used to describe a group of symptoms caused by different diseases that slowly damage the brain. Damage to brain cells can lead to difficulties in memory, thinking, understanding, communication, behaviour, and even personality. Over time, these changes become more serious and begin to affect daily life.
In a recent opinion article, Professor Eef Hogervorst from Loughborough University discussed new research about diet and dementia risk. A large study carried out in Sweden has attracted attention because it suggests that eating certain full-fat dairy products may be linked to a lower risk of dementia. The Swedish study followed 27,670 middle-aged and older adults for 25 years. During this time, 3,208 participants developed dementia. Researchers found that people who ate more than 50 grams of full-fat cheese per day had a 13% to 17% lower risk of developing Alzheimer’s disease.
However, only those without a known genetic risk for Alzheimer’s disease experienced this benefit. For those with a higher genetic risk, eating more cheese did not seem to make a difference. The study also reported that people who consumed more than 20 grams of full-fat cream per day had a 16% to 24% lower risk of dementia overall. Interestingly, no similar link was found for low-fat milk, high-fat milk, fermented milk, non-fermented milk, or low-fat cream. These findings are surprising because public health advice has often encouraged people to choose low-fat dairy products to protect heart health.
Heart disease and dementia share many of the same risk factors, including high blood pressure, diabetes, and obesity. For this reason, experts have long believed that lowering saturated fat intake would also help reduce dementia risk. Combining results from earlier studies, researchers find some evidence linking cheese to a lower risk of heart disease. In addition, full-fat dairy products do not always appear to increase the risk of cardiovascular problems as once thought. However, studies looking specifically at dairy and brain health have produced mixed results.
Research conducted in Asian countries is more likely to report benefits of dairy consumption for brain function. In contrast, many European studies show an unclear or negligible effect. One possible reason is that people in many Asian countries traditionally consume much less dairy than those in Europe. Small amounts of dairy might have different effects compared to larger amounts. For example, one study in Japan found that people who ate cheese had a lower risk of dementia. However, the study’s overall cheese consumption was very low, and a cheese company funded the research.
Another Japanese study supported by government funding did not find any protective effect from cheese. Some long-term European studies have shown possible benefits. A Finnish study that followed 2,497 middle-aged men for 22 years found that cheese was the only food linked to a lower risk of dementia, with a 28% reduction. In that same study, higher milk and processed red meat consumption were linked to worse performance on memory tests, while eating more fish was linked to better results. A large study in the UK that tracked nearly 250,000 people found that eating fish two to four times per week, fruit daily, and cheese once a week was associated with a lower risk of dementia.
However, all of these studies have limitations. Most rely on self-reported diets, which means participants may not accurately remember what they eat. In addition, early memory problems could change both eating habits and the ability to report food intake correctly. To address this issue, the Swedish researchers used additional methods to reduce errors and improve the reliability of their findings.
